The pedigree of TDE4 is shown in FIG. 1. In 1973, pollen from Encore mandarin (unpatented to Applicant's knowledge) was applied to stigmas of a tetraploid (Temple×4N Dancy) hybrid (unpatented to Applicants' knowledge) and the pollinated flowers were bagged to prevent insect pollination. Fruits were collected in winter 1974, seeds extracted from each fruit, and each seed was planted. The chromosome number of each seedling was determined and those identified as triploid seedlings were budded onto Troyer rootstock. The resulting trees were planted in the field in Riverside, Calif. in 1976. These trees were evaluated for tree vigor, bearing, and seediness, fruit flavor, fruit color, and other fruit quality traits from bearing until 1985. Five trees were selected from the original population and repropagated by budding onto C-32 citrange, C-35 citrange, Troyer citrange, and trifoliate orange rootstocks. Two trees of the selection now called TDE4 were planted in the field in Riverside in 1987. When they began fruiting (approximately in 1990), these trees were evaluated for the same tree and fruit quality traits as the original trees. In 1987, the selection now called TDE4 was chosen for additional testing because it combined medium or large fruit size, low seed number, rich fruit flavor, deep orange rind and flesh color, and acceptable peelability. Budwood of this selection was tested for viruses and other pathogens by the Citrus Clonal Protection Program and virus-free bud source trees were planted in Lindcove Research and Extension Center, Exeter, Calif. in 1991.
Using this virus-free budwood source, additional trees were propagated and planted at several California locations between 1993 and 1996. These included one location in the Coachella Valley (the Coachella Valley Agricultural Research Station-CVARS, 8 trees), Ojai (12 trees ) and Santa Paula (5 trees) in Ventura Co., and two locations in the San Joaquin Valley, (Lindcove Research and Extension Center, 8 trees, and Orange Cove, 8 trees). These trial plantings provide most of the available data on TDE4. Several different rootstocks have been used in these evaluations, including Carrizo citrange, C35 citrange, Rich 16-6 trifoliate, Cleopatra mandarin, and Schaub rough lemon. In general, no major effects of these rootstocks on fruit quality of TDE4 were observed, and no incompatiblities have been evident, but longevity of trees on various rootstocks is not known. Effects of rootstocks on tree size are discussed below.